A bipolar device, a CMOS (Complementary Metal Oxide Semiconductor), and a DMOS (Double diffusion MOS) can be formed in a single wafer by using a BCD process. Besides the bipolar device, the CMOS and the DMOS, a logic circuit, a PMOS, an NMOS, a resistor, a capacitor and a diode can be integrated in a single chip through the BCD process. For instance, a bipolar transistor can be manufactured while the CMOS and the DMOS are being manufactured through the BCD process.
The bipolar transistor has a structure employing a junction emitter. Therefore, in the case of the bipolar transistor manufactured through the related BCD process, it processes to improve the high frequency characteristics, to increase the amplification gain and breakdown voltage and to widen the operational range are limited.